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      1 // Copyright 2012 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      3 // modification, are permitted provided that the following conditions are
      4 // met:
      5 //
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
     12 //     * Neither the name of Google Inc. nor the names of its
     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 
     28 #ifndef V8_ISOLATE_H_
     29 #define V8_ISOLATE_H_
     30 
     31 #include "../include/v8-debug.h"
     32 #include "allocation.h"
     33 #include "apiutils.h"
     34 #include "atomicops.h"
     35 #include "builtins.h"
     36 #include "contexts.h"
     37 #include "execution.h"
     38 #include "frames.h"
     39 #include "date.h"
     40 #include "global-handles.h"
     41 #include "handles.h"
     42 #include "hashmap.h"
     43 #include "heap.h"
     44 #include "regexp-stack.h"
     45 #include "runtime-profiler.h"
     46 #include "runtime.h"
     47 #include "zone.h"
     48 
     49 namespace v8 {
     50 namespace internal {
     51 
     52 class Bootstrapper;
     53 class CodeGenerator;
     54 class CodeRange;
     55 class CompilationCache;
     56 class ContextSlotCache;
     57 class ContextSwitcher;
     58 class Counters;
     59 class CpuFeatures;
     60 class CpuProfiler;
     61 class DeoptimizerData;
     62 class Deserializer;
     63 class EmptyStatement;
     64 class ExternalReferenceTable;
     65 class Factory;
     66 class FunctionInfoListener;
     67 class HandleScopeImplementer;
     68 class HeapProfiler;
     69 class InlineRuntimeFunctionsTable;
     70 class NoAllocationStringAllocator;
     71 class InnerPointerToCodeCache;
     72 class PreallocatedMemoryThread;
     73 class RegExpStack;
     74 class SaveContext;
     75 class UnicodeCache;
     76 class StringInputBuffer;
     77 class StringTracker;
     78 class StubCache;
     79 class ThreadManager;
     80 class ThreadState;
     81 class ThreadVisitor;  // Defined in v8threads.h
     82 class VMState;
     83 
     84 // 'void function pointer', used to roundtrip the
     85 // ExternalReference::ExternalReferenceRedirector since we can not include
     86 // assembler.h, where it is defined, here.
     87 typedef void* ExternalReferenceRedirectorPointer();
     88 
     89 
     90 #ifdef ENABLE_DEBUGGER_SUPPORT
     91 class Debug;
     92 class Debugger;
     93 class DebuggerAgent;
     94 #endif
     95 
     96 #if !defined(__arm__) && defined(V8_TARGET_ARCH_ARM) || \
     97     !defined(__mips__) && defined(V8_TARGET_ARCH_MIPS)
     98 class Redirection;
     99 class Simulator;
    100 #endif
    101 
    102 
    103 // Static indirection table for handles to constants.  If a frame
    104 // element represents a constant, the data contains an index into
    105 // this table of handles to the actual constants.
    106 // Static indirection table for handles to constants.  If a Result
    107 // represents a constant, the data contains an index into this table
    108 // of handles to the actual constants.
    109 typedef ZoneList<Handle<Object> > ZoneObjectList;
    110 
    111 #define RETURN_IF_SCHEDULED_EXCEPTION(isolate)            \
    112   do {                                                    \
    113     Isolate* __isolate__ = (isolate);                     \
    114     if (__isolate__->has_scheduled_exception()) {         \
    115       return __isolate__->PromoteScheduledException();    \
    116     }                                                     \
    117   } while (false)
    118 
    119 #define RETURN_IF_EMPTY_HANDLE_VALUE(isolate, call, value) \
    120   do {                                                     \
    121     if ((call).is_null()) {                                \
    122       ASSERT((isolate)->has_pending_exception());          \
    123       return (value);                                      \
    124     }                                                      \
    125   } while (false)
    126 
    127 #define CHECK_NOT_EMPTY_HANDLE(isolate, call)     \
    128   do {                                            \
    129     ASSERT(!(isolate)->has_pending_exception());  \
    130     CHECK(!(call).is_null());                     \
    131     CHECK(!(isolate)->has_pending_exception());   \
    132   } while (false)
    133 
    134 #define RETURN_IF_EMPTY_HANDLE(isolate, call)                       \
    135   RETURN_IF_EMPTY_HANDLE_VALUE(isolate, call, Failure::Exception())
    136 
    137 #define FOR_EACH_ISOLATE_ADDRESS_NAME(C)                \
    138   C(Handler, handler)                                   \
    139   C(CEntryFP, c_entry_fp)                               \
    140   C(Context, context)                                   \
    141   C(PendingException, pending_exception)                \
    142   C(ExternalCaughtException, external_caught_exception) \
    143   C(JSEntrySP, js_entry_sp)
    144 
    145 
    146 // Platform-independent, reliable thread identifier.
    147 class ThreadId {
    148  public:
    149   // Creates an invalid ThreadId.
    150   ThreadId() : id_(kInvalidId) {}
    151 
    152   // Returns ThreadId for current thread.
    153   static ThreadId Current() { return ThreadId(GetCurrentThreadId()); }
    154 
    155   // Returns invalid ThreadId (guaranteed not to be equal to any thread).
    156   static ThreadId Invalid() { return ThreadId(kInvalidId); }
    157 
    158   // Compares ThreadIds for equality.
    159   INLINE(bool Equals(const ThreadId& other) const) {
    160     return id_ == other.id_;
    161   }
    162 
    163   // Checks whether this ThreadId refers to any thread.
    164   INLINE(bool IsValid() const) {
    165     return id_ != kInvalidId;
    166   }
    167 
    168   // Converts ThreadId to an integer representation
    169   // (required for public API: V8::V8::GetCurrentThreadId).
    170   int ToInteger() const { return id_; }
    171 
    172   // Converts ThreadId to an integer representation
    173   // (required for public API: V8::V8::TerminateExecution).
    174   static ThreadId FromInteger(int id) { return ThreadId(id); }
    175 
    176  private:
    177   static const int kInvalidId = -1;
    178 
    179   explicit ThreadId(int id) : id_(id) {}
    180 
    181   static int AllocateThreadId();
    182 
    183   static int GetCurrentThreadId();
    184 
    185   int id_;
    186 
    187   static Atomic32 highest_thread_id_;
    188 
    189   friend class Isolate;
    190 };
    191 
    192 
    193 class ThreadLocalTop BASE_EMBEDDED {
    194  public:
    195   // Does early low-level initialization that does not depend on the
    196   // isolate being present.
    197   ThreadLocalTop();
    198 
    199   // Initialize the thread data.
    200   void Initialize();
    201 
    202   // Get the top C++ try catch handler or NULL if none are registered.
    203   //
    204   // This method is not guarenteed to return an address that can be
    205   // used for comparison with addresses into the JS stack.  If such an
    206   // address is needed, use try_catch_handler_address.
    207   v8::TryCatch* TryCatchHandler();
    208 
    209   // Get the address of the top C++ try catch handler or NULL if
    210   // none are registered.
    211   //
    212   // This method always returns an address that can be compared to
    213   // pointers into the JavaScript stack.  When running on actual
    214   // hardware, try_catch_handler_address and TryCatchHandler return
    215   // the same pointer.  When running on a simulator with a separate JS
    216   // stack, try_catch_handler_address returns a JS stack address that
    217   // corresponds to the place on the JS stack where the C++ handler
    218   // would have been if the stack were not separate.
    219   inline Address try_catch_handler_address() {
    220     return try_catch_handler_address_;
    221   }
    222 
    223   // Set the address of the top C++ try catch handler.
    224   inline void set_try_catch_handler_address(Address address) {
    225     try_catch_handler_address_ = address;
    226   }
    227 
    228   void Free() {
    229     ASSERT(!has_pending_message_);
    230     ASSERT(!external_caught_exception_);
    231     ASSERT(try_catch_handler_address_ == NULL);
    232   }
    233 
    234   Isolate* isolate_;
    235   // The context where the current execution method is created and for variable
    236   // lookups.
    237   Context* context_;
    238   ThreadId thread_id_;
    239   MaybeObject* pending_exception_;
    240   bool has_pending_message_;
    241   Object* pending_message_obj_;
    242   Script* pending_message_script_;
    243   int pending_message_start_pos_;
    244   int pending_message_end_pos_;
    245   // Use a separate value for scheduled exceptions to preserve the
    246   // invariants that hold about pending_exception.  We may want to
    247   // unify them later.
    248   MaybeObject* scheduled_exception_;
    249   bool external_caught_exception_;
    250   SaveContext* save_context_;
    251   v8::TryCatch* catcher_;
    252 
    253   // Stack.
    254   Address c_entry_fp_;  // the frame pointer of the top c entry frame
    255   Address handler_;   // try-blocks are chained through the stack
    256 
    257 #ifdef USE_SIMULATOR
    258 #if defined(V8_TARGET_ARCH_ARM) || defined(V8_TARGET_ARCH_MIPS)
    259   Simulator* simulator_;
    260 #endif
    261 #endif  // USE_SIMULATOR
    262 
    263   Address js_entry_sp_;  // the stack pointer of the bottom JS entry frame
    264   Address external_callback_;  // the external callback we're currently in
    265   StateTag current_vm_state_;
    266 
    267   // Generated code scratch locations.
    268   int32_t formal_count_;
    269 
    270   // Call back function to report unsafe JS accesses.
    271   v8::FailedAccessCheckCallback failed_access_check_callback_;
    272 
    273   // Head of the list of live LookupResults.
    274   LookupResult* top_lookup_result_;
    275 
    276   // Whether out of memory exceptions should be ignored.
    277   bool ignore_out_of_memory_;
    278 
    279  private:
    280   void InitializeInternal();
    281 
    282   Address try_catch_handler_address_;
    283 };
    284 
    285 
    286 #ifdef ENABLE_DEBUGGER_SUPPORT
    287 
    288 #define ISOLATE_DEBUGGER_INIT_LIST(V)                                          \
    289   V(v8::Debug::EventCallback, debug_event_callback, NULL)                      \
    290   V(DebuggerAgent*, debugger_agent_instance, NULL)
    291 #else
    292 
    293 #define ISOLATE_DEBUGGER_INIT_LIST(V)
    294 
    295 #endif
    296 
    297 #ifdef DEBUG
    298 
    299 #define ISOLATE_INIT_DEBUG_ARRAY_LIST(V)                                       \
    300   V(CommentStatistic, paged_space_comments_statistics,                         \
    301       CommentStatistic::kMaxComments + 1)
    302 #else
    303 
    304 #define ISOLATE_INIT_DEBUG_ARRAY_LIST(V)
    305 
    306 #endif
    307 
    308 #define ISOLATE_INIT_ARRAY_LIST(V)                                             \
    309   /* SerializerDeserializer state. */                                          \
    310   V(Object*, serialize_partial_snapshot_cache, kPartialSnapshotCacheCapacity)  \
    311   V(int, jsregexp_static_offsets_vector, kJSRegexpStaticOffsetsVectorSize)     \
    312   V(int, bad_char_shift_table, kUC16AlphabetSize)                              \
    313   V(int, good_suffix_shift_table, (kBMMaxShift + 1))                           \
    314   V(int, suffix_table, (kBMMaxShift + 1))                                      \
    315   V(uint32_t, private_random_seed, 2)                                          \
    316   ISOLATE_INIT_DEBUG_ARRAY_LIST(V)
    317 
    318 typedef List<HeapObject*, PreallocatedStorage> DebugObjectCache;
    319 
    320 #define ISOLATE_INIT_LIST(V)                                                   \
    321   /* SerializerDeserializer state. */                                          \
    322   V(int, serialize_partial_snapshot_cache_length, 0)                           \
    323   /* Assembler state. */                                                       \
    324   /* A previously allocated buffer of kMinimalBufferSize bytes, or NULL. */    \
    325   V(byte*, assembler_spare_buffer, NULL)                                       \
    326   V(FatalErrorCallback, exception_behavior, NULL)                              \
    327   V(AllowCodeGenerationFromStringsCallback, allow_code_gen_callback, NULL)     \
    328   V(v8::Debug::MessageHandler, message_handler, NULL)                          \
    329   /* To distinguish the function templates, so that we can find them in the */ \
    330   /* function cache of the global context. */                                  \
    331   V(int, next_serial_number, 0)                                                \
    332   V(ExternalReferenceRedirectorPointer*, external_reference_redirector, NULL)  \
    333   V(bool, always_allow_natives_syntax, false)                                  \
    334   /* Part of the state of liveedit. */                                         \
    335   V(FunctionInfoListener*, active_function_info_listener, NULL)                \
    336   /* State for Relocatable. */                                                 \
    337   V(Relocatable*, relocatable_top, NULL)                                       \
    338   /* State for CodeEntry in profile-generator. */                              \
    339   V(CodeGenerator*, current_code_generator, NULL)                              \
    340   V(bool, jump_target_compiling_deferred_code, false)                          \
    341   V(DebugObjectCache*, string_stream_debug_object_cache, NULL)                 \
    342   V(Object*, string_stream_current_security_token, NULL)                       \
    343   /* TODO(isolates): Release this on destruction? */                           \
    344   V(int*, irregexp_interpreter_backtrack_stack_cache, NULL)                    \
    345   /* Serializer state. */                                                      \
    346   V(ExternalReferenceTable*, external_reference_table, NULL)                   \
    347   /* AstNode state. */                                                         \
    348   V(int, ast_node_id, 0)                                                       \
    349   V(unsigned, ast_node_count, 0)                                               \
    350   /* SafeStackFrameIterator activations count. */                              \
    351   V(int, safe_stack_iterator_counter, 0)                                       \
    352   V(uint64_t, enabled_cpu_features, 0)                                         \
    353   V(CpuProfiler*, cpu_profiler, NULL)                                          \
    354   V(HeapProfiler*, heap_profiler, NULL)                                        \
    355   ISOLATE_DEBUGGER_INIT_LIST(V)
    356 
    357 class Isolate {
    358   // These forward declarations are required to make the friend declarations in
    359   // PerIsolateThreadData work on some older versions of gcc.
    360   class ThreadDataTable;
    361   class EntryStackItem;
    362  public:
    363   ~Isolate();
    364 
    365   // A thread has a PerIsolateThreadData instance for each isolate that it has
    366   // entered. That instance is allocated when the isolate is initially entered
    367   // and reused on subsequent entries.
    368   class PerIsolateThreadData {
    369    public:
    370     PerIsolateThreadData(Isolate* isolate, ThreadId thread_id)
    371         : isolate_(isolate),
    372           thread_id_(thread_id),
    373           stack_limit_(0),
    374           thread_state_(NULL),
    375 #if !defined(__arm__) && defined(V8_TARGET_ARCH_ARM) || \
    376     !defined(__mips__) && defined(V8_TARGET_ARCH_MIPS)
    377           simulator_(NULL),
    378 #endif
    379           next_(NULL),
    380           prev_(NULL) { }
    381     Isolate* isolate() const { return isolate_; }
    382     ThreadId thread_id() const { return thread_id_; }
    383     void set_stack_limit(uintptr_t value) { stack_limit_ = value; }
    384     uintptr_t stack_limit() const { return stack_limit_; }
    385     ThreadState* thread_state() const { return thread_state_; }
    386     void set_thread_state(ThreadState* value) { thread_state_ = value; }
    387 
    388 #if !defined(__arm__) && defined(V8_TARGET_ARCH_ARM) || \
    389     !defined(__mips__) && defined(V8_TARGET_ARCH_MIPS)
    390     Simulator* simulator() const { return simulator_; }
    391     void set_simulator(Simulator* simulator) {
    392       simulator_ = simulator;
    393     }
    394 #endif
    395 
    396     bool Matches(Isolate* isolate, ThreadId thread_id) const {
    397       return isolate_ == isolate && thread_id_.Equals(thread_id);
    398     }
    399 
    400    private:
    401     Isolate* isolate_;
    402     ThreadId thread_id_;
    403     uintptr_t stack_limit_;
    404     ThreadState* thread_state_;
    405 
    406 #if !defined(__arm__) && defined(V8_TARGET_ARCH_ARM) || \
    407     !defined(__mips__) && defined(V8_TARGET_ARCH_MIPS)
    408     Simulator* simulator_;
    409 #endif
    410 
    411     PerIsolateThreadData* next_;
    412     PerIsolateThreadData* prev_;
    413 
    414     friend class Isolate;
    415     friend class ThreadDataTable;
    416     friend class EntryStackItem;
    417 
    418     DISALLOW_COPY_AND_ASSIGN(PerIsolateThreadData);
    419   };
    420 
    421 
    422   enum AddressId {
    423 #define DECLARE_ENUM(CamelName, hacker_name) k##CamelName##Address,
    424     FOR_EACH_ISOLATE_ADDRESS_NAME(DECLARE_ENUM)
    425 #undef C
    426     kIsolateAddressCount
    427   };
    428 
    429   // Returns the PerIsolateThreadData for the current thread (or NULL if one is
    430   // not currently set).
    431   static PerIsolateThreadData* CurrentPerIsolateThreadData() {
    432     return reinterpret_cast<PerIsolateThreadData*>(
    433         Thread::GetThreadLocal(per_isolate_thread_data_key_));
    434   }
    435 
    436   // Returns the isolate inside which the current thread is running.
    437   INLINE(static Isolate* Current()) {
    438     Isolate* isolate = reinterpret_cast<Isolate*>(
    439         Thread::GetExistingThreadLocal(isolate_key_));
    440     ASSERT(isolate != NULL);
    441     return isolate;
    442   }
    443 
    444   INLINE(static Isolate* UncheckedCurrent()) {
    445     return reinterpret_cast<Isolate*>(Thread::GetThreadLocal(isolate_key_));
    446   }
    447 
    448   // Usually called by Init(), but can be called early e.g. to allow
    449   // testing components that require logging but not the whole
    450   // isolate.
    451   //
    452   // Safe to call more than once.
    453   void InitializeLoggingAndCounters();
    454 
    455   bool Init(Deserializer* des);
    456 
    457   bool IsInitialized() { return state_ == INITIALIZED; }
    458 
    459   // True if at least one thread Enter'ed this isolate.
    460   bool IsInUse() { return entry_stack_ != NULL; }
    461 
    462   // Destroys the non-default isolates.
    463   // Sets default isolate into "has_been_disposed" state rather then destroying,
    464   // for legacy API reasons.
    465   void TearDown();
    466 
    467   bool IsDefaultIsolate() const { return this == default_isolate_; }
    468 
    469   // Ensures that process-wide resources and the default isolate have been
    470   // allocated. It is only necessary to call this method in rare cases, for
    471   // example if you are using V8 from within the body of a static initializer.
    472   // Safe to call multiple times.
    473   static void EnsureDefaultIsolate();
    474 
    475   // Find the PerThread for this particular (isolate, thread) combination
    476   // If one does not yet exist, return null.
    477   PerIsolateThreadData* FindPerThreadDataForThisThread();
    478 
    479 #ifdef ENABLE_DEBUGGER_SUPPORT
    480   // Get the debugger from the default isolate. Preinitializes the
    481   // default isolate if needed.
    482   static Debugger* GetDefaultIsolateDebugger();
    483 #endif
    484 
    485   // Get the stack guard from the default isolate. Preinitializes the
    486   // default isolate if needed.
    487   static StackGuard* GetDefaultIsolateStackGuard();
    488 
    489   // Returns the key used to store the pointer to the current isolate.
    490   // Used internally for V8 threads that do not execute JavaScript but still
    491   // are part of the domain of an isolate (like the context switcher).
    492   static Thread::LocalStorageKey isolate_key() {
    493     return isolate_key_;
    494   }
    495 
    496   // Returns the key used to store process-wide thread IDs.
    497   static Thread::LocalStorageKey thread_id_key() {
    498     return thread_id_key_;
    499   }
    500 
    501   static Thread::LocalStorageKey per_isolate_thread_data_key();
    502 
    503   // If a client attempts to create a Locker without specifying an isolate,
    504   // we assume that the client is using legacy behavior. Set up the current
    505   // thread to be inside the implicit isolate (or fail a check if we have
    506   // switched to non-legacy behavior).
    507   static void EnterDefaultIsolate();
    508 
    509   // Mutex for serializing access to break control structures.
    510   Mutex* break_access() { return break_access_; }
    511 
    512   // Mutex for serializing access to debugger.
    513   Mutex* debugger_access() { return debugger_access_; }
    514 
    515   Address get_address_from_id(AddressId id);
    516 
    517   // Access to top context (where the current function object was created).
    518   Context* context() { return thread_local_top_.context_; }
    519   void set_context(Context* context) {
    520     ASSERT(context == NULL || context->IsContext());
    521     thread_local_top_.context_ = context;
    522   }
    523   Context** context_address() { return &thread_local_top_.context_; }
    524 
    525   SaveContext* save_context() {return thread_local_top_.save_context_; }
    526   void set_save_context(SaveContext* save) {
    527     thread_local_top_.save_context_ = save;
    528   }
    529 
    530   // Access to current thread id.
    531   ThreadId thread_id() { return thread_local_top_.thread_id_; }
    532   void set_thread_id(ThreadId id) { thread_local_top_.thread_id_ = id; }
    533 
    534   // Interface to pending exception.
    535   MaybeObject* pending_exception() {
    536     ASSERT(has_pending_exception());
    537     return thread_local_top_.pending_exception_;
    538   }
    539   bool external_caught_exception() {
    540     return thread_local_top_.external_caught_exception_;
    541   }
    542   void set_external_caught_exception(bool value) {
    543     thread_local_top_.external_caught_exception_ = value;
    544   }
    545   void set_pending_exception(MaybeObject* exception) {
    546     thread_local_top_.pending_exception_ = exception;
    547   }
    548   void clear_pending_exception() {
    549     thread_local_top_.pending_exception_ = heap_.the_hole_value();
    550   }
    551   MaybeObject** pending_exception_address() {
    552     return &thread_local_top_.pending_exception_;
    553   }
    554   bool has_pending_exception() {
    555     return !thread_local_top_.pending_exception_->IsTheHole();
    556   }
    557   void clear_pending_message() {
    558     thread_local_top_.has_pending_message_ = false;
    559     thread_local_top_.pending_message_obj_ = heap_.the_hole_value();
    560     thread_local_top_.pending_message_script_ = NULL;
    561   }
    562   v8::TryCatch* try_catch_handler() {
    563     return thread_local_top_.TryCatchHandler();
    564   }
    565   Address try_catch_handler_address() {
    566     return thread_local_top_.try_catch_handler_address();
    567   }
    568   bool* external_caught_exception_address() {
    569     return &thread_local_top_.external_caught_exception_;
    570   }
    571   v8::TryCatch* catcher() {
    572     return thread_local_top_.catcher_;
    573   }
    574   void set_catcher(v8::TryCatch* catcher) {
    575     thread_local_top_.catcher_ = catcher;
    576   }
    577 
    578   MaybeObject** scheduled_exception_address() {
    579     return &thread_local_top_.scheduled_exception_;
    580   }
    581   MaybeObject* scheduled_exception() {
    582     ASSERT(has_scheduled_exception());
    583     return thread_local_top_.scheduled_exception_;
    584   }
    585   bool has_scheduled_exception() {
    586     return thread_local_top_.scheduled_exception_ != heap_.the_hole_value();
    587   }
    588   void clear_scheduled_exception() {
    589     thread_local_top_.scheduled_exception_ = heap_.the_hole_value();
    590   }
    591 
    592   bool IsExternallyCaught();
    593 
    594   bool is_catchable_by_javascript(MaybeObject* exception) {
    595     return (exception != Failure::OutOfMemoryException()) &&
    596         (exception != heap()->termination_exception());
    597   }
    598 
    599   // JS execution stack (see frames.h).
    600   static Address c_entry_fp(ThreadLocalTop* thread) {
    601     return thread->c_entry_fp_;
    602   }
    603   static Address handler(ThreadLocalTop* thread) { return thread->handler_; }
    604 
    605   inline Address* c_entry_fp_address() {
    606     return &thread_local_top_.c_entry_fp_;
    607   }
    608   inline Address* handler_address() { return &thread_local_top_.handler_; }
    609 
    610   // Bottom JS entry (see StackTracer::Trace in log.cc).
    611   static Address js_entry_sp(ThreadLocalTop* thread) {
    612     return thread->js_entry_sp_;
    613   }
    614   inline Address* js_entry_sp_address() {
    615     return &thread_local_top_.js_entry_sp_;
    616   }
    617 
    618   // Generated code scratch locations.
    619   void* formal_count_address() { return &thread_local_top_.formal_count_; }
    620 
    621   // Returns the global object of the current context. It could be
    622   // a builtin object, or a JS global object.
    623   Handle<GlobalObject> global() {
    624     return Handle<GlobalObject>(context()->global());
    625   }
    626 
    627   // Returns the global proxy object of the current context.
    628   Object* global_proxy() {
    629     return context()->global_proxy();
    630   }
    631 
    632   Handle<JSBuiltinsObject> js_builtins_object() {
    633     return Handle<JSBuiltinsObject>(thread_local_top_.context_->builtins());
    634   }
    635 
    636   static int ArchiveSpacePerThread() { return sizeof(ThreadLocalTop); }
    637   void FreeThreadResources() { thread_local_top_.Free(); }
    638 
    639   // This method is called by the api after operations that may throw
    640   // exceptions.  If an exception was thrown and not handled by an external
    641   // handler the exception is scheduled to be rethrown when we return to running
    642   // JavaScript code.  If an exception is scheduled true is returned.
    643   bool OptionalRescheduleException(bool is_bottom_call);
    644 
    645   class ExceptionScope {
    646    public:
    647     explicit ExceptionScope(Isolate* isolate) :
    648       // Scope currently can only be used for regular exceptions, not
    649       // failures like OOM or termination exception.
    650       isolate_(isolate),
    651       pending_exception_(isolate_->pending_exception()->ToObjectUnchecked()),
    652       catcher_(isolate_->catcher())
    653     { }
    654 
    655     ~ExceptionScope() {
    656       isolate_->set_catcher(catcher_);
    657       isolate_->set_pending_exception(*pending_exception_);
    658     }
    659 
    660    private:
    661     Isolate* isolate_;
    662     Handle<Object> pending_exception_;
    663     v8::TryCatch* catcher_;
    664   };
    665 
    666   void SetCaptureStackTraceForUncaughtExceptions(
    667       bool capture,
    668       int frame_limit,
    669       StackTrace::StackTraceOptions options);
    670 
    671   // Tells whether the current context has experienced an out of memory
    672   // exception.
    673   bool is_out_of_memory();
    674   bool ignore_out_of_memory() {
    675     return thread_local_top_.ignore_out_of_memory_;
    676   }
    677   void set_ignore_out_of_memory(bool value) {
    678     thread_local_top_.ignore_out_of_memory_ = value;
    679   }
    680 
    681   void PrintCurrentStackTrace(FILE* out);
    682   void PrintStackTrace(FILE* out, char* thread_data);
    683   void PrintStack(StringStream* accumulator);
    684   void PrintStack();
    685   Handle<String> StackTraceString();
    686   Handle<JSArray> CaptureCurrentStackTrace(
    687       int frame_limit,
    688       StackTrace::StackTraceOptions options);
    689 
    690   void CaptureAndSetCurrentStackTraceFor(Handle<JSObject> error_object);
    691 
    692   // Returns if the top context may access the given global object. If
    693   // the result is false, the pending exception is guaranteed to be
    694   // set.
    695   bool MayNamedAccess(JSObject* receiver,
    696                       Object* key,
    697                       v8::AccessType type);
    698   bool MayIndexedAccess(JSObject* receiver,
    699                         uint32_t index,
    700                         v8::AccessType type);
    701 
    702   void SetFailedAccessCheckCallback(v8::FailedAccessCheckCallback callback);
    703   void ReportFailedAccessCheck(JSObject* receiver, v8::AccessType type);
    704 
    705   // Exception throwing support. The caller should use the result
    706   // of Throw() as its return value.
    707   Failure* Throw(Object* exception, MessageLocation* location = NULL);
    708   // Re-throw an exception.  This involves no error reporting since
    709   // error reporting was handled when the exception was thrown
    710   // originally.
    711   Failure* ReThrow(MaybeObject* exception, MessageLocation* location = NULL);
    712   void ScheduleThrow(Object* exception);
    713   void ReportPendingMessages();
    714   Failure* ThrowIllegalOperation();
    715 
    716   // Promote a scheduled exception to pending. Asserts has_scheduled_exception.
    717   Failure* PromoteScheduledException();
    718   void DoThrow(Object* exception, MessageLocation* location);
    719   // Checks if exception should be reported and finds out if it's
    720   // caught externally.
    721   bool ShouldReportException(bool* can_be_caught_externally,
    722                              bool catchable_by_javascript);
    723 
    724   // Attempts to compute the current source location, storing the
    725   // result in the target out parameter.
    726   void ComputeLocation(MessageLocation* target);
    727 
    728   // Override command line flag.
    729   void TraceException(bool flag);
    730 
    731   // Out of resource exception helpers.
    732   Failure* StackOverflow();
    733   Failure* TerminateExecution();
    734 
    735   // Administration
    736   void Iterate(ObjectVisitor* v);
    737   void Iterate(ObjectVisitor* v, ThreadLocalTop* t);
    738   char* Iterate(ObjectVisitor* v, char* t);
    739   void IterateThread(ThreadVisitor* v);
    740   void IterateThread(ThreadVisitor* v, char* t);
    741 
    742 
    743   // Returns the current global context.
    744   Handle<Context> global_context();
    745 
    746   // Returns the global context of the calling JavaScript code.  That
    747   // is, the global context of the top-most JavaScript frame.
    748   Handle<Context> GetCallingGlobalContext();
    749 
    750   void RegisterTryCatchHandler(v8::TryCatch* that);
    751   void UnregisterTryCatchHandler(v8::TryCatch* that);
    752 
    753   char* ArchiveThread(char* to);
    754   char* RestoreThread(char* from);
    755 
    756   static const char* const kStackOverflowMessage;
    757 
    758   static const int kUC16AlphabetSize = 256;  // See StringSearchBase.
    759   static const int kBMMaxShift = 250;        // See StringSearchBase.
    760 
    761   // Accessors.
    762 #define GLOBAL_ACCESSOR(type, name, initialvalue)                       \
    763   inline type name() const {                                            \
    764     ASSERT(OFFSET_OF(Isolate, name##_) == name##_debug_offset_);        \
    765     return name##_;                                                     \
    766   }                                                                     \
    767   inline void set_##name(type value) {                                  \
    768     ASSERT(OFFSET_OF(Isolate, name##_) == name##_debug_offset_);        \
    769     name##_ = value;                                                    \
    770   }
    771   ISOLATE_INIT_LIST(GLOBAL_ACCESSOR)
    772 #undef GLOBAL_ACCESSOR
    773 
    774 #define GLOBAL_ARRAY_ACCESSOR(type, name, length)                       \
    775   inline type* name() {                                                 \
    776     ASSERT(OFFSET_OF(Isolate, name##_) == name##_debug_offset_);        \
    777     return &(name##_)[0];                                               \
    778   }
    779   ISOLATE_INIT_ARRAY_LIST(GLOBAL_ARRAY_ACCESSOR)
    780 #undef GLOBAL_ARRAY_ACCESSOR
    781 
    782 #define GLOBAL_CONTEXT_FIELD_ACCESSOR(index, type, name)      \
    783   Handle<type> name() {                                       \
    784     return Handle<type>(context()->global_context()->name()); \
    785   }
    786   GLOBAL_CONTEXT_FIELDS(GLOBAL_CONTEXT_FIELD_ACCESSOR)
    787 #undef GLOBAL_CONTEXT_FIELD_ACCESSOR
    788 
    789   Bootstrapper* bootstrapper() { return bootstrapper_; }
    790   Counters* counters() {
    791     // Call InitializeLoggingAndCounters() if logging is needed before
    792     // the isolate is fully initialized.
    793     ASSERT(counters_ != NULL);
    794     return counters_;
    795   }
    796   CodeRange* code_range() { return code_range_; }
    797   RuntimeProfiler* runtime_profiler() { return runtime_profiler_; }
    798   CompilationCache* compilation_cache() { return compilation_cache_; }
    799   Logger* logger() {
    800     // Call InitializeLoggingAndCounters() if logging is needed before
    801     // the isolate is fully initialized.
    802     ASSERT(logger_ != NULL);
    803     return logger_;
    804   }
    805   StackGuard* stack_guard() { return &stack_guard_; }
    806   Heap* heap() { return &heap_; }
    807   StatsTable* stats_table();
    808   StubCache* stub_cache() { return stub_cache_; }
    809   DeoptimizerData* deoptimizer_data() { return deoptimizer_data_; }
    810   ThreadLocalTop* thread_local_top() { return &thread_local_top_; }
    811 
    812   TranscendentalCache* transcendental_cache() const {
    813     return transcendental_cache_;
    814   }
    815 
    816   MemoryAllocator* memory_allocator() {
    817     return memory_allocator_;
    818   }
    819 
    820   KeyedLookupCache* keyed_lookup_cache() {
    821     return keyed_lookup_cache_;
    822   }
    823 
    824   ContextSlotCache* context_slot_cache() {
    825     return context_slot_cache_;
    826   }
    827 
    828   DescriptorLookupCache* descriptor_lookup_cache() {
    829     return descriptor_lookup_cache_;
    830   }
    831 
    832   v8::ImplementationUtilities::HandleScopeData* handle_scope_data() {
    833     return &handle_scope_data_;
    834   }
    835   HandleScopeImplementer* handle_scope_implementer() {
    836     ASSERT(handle_scope_implementer_);
    837     return handle_scope_implementer_;
    838   }
    839   Zone* zone() { return &zone_; }
    840 
    841   UnicodeCache* unicode_cache() {
    842     return unicode_cache_;
    843   }
    844 
    845   InnerPointerToCodeCache* inner_pointer_to_code_cache() {
    846     return inner_pointer_to_code_cache_;
    847   }
    848 
    849   StringInputBuffer* write_input_buffer() { return write_input_buffer_; }
    850 
    851   GlobalHandles* global_handles() { return global_handles_; }
    852 
    853   ThreadManager* thread_manager() { return thread_manager_; }
    854 
    855   ContextSwitcher* context_switcher() { return context_switcher_; }
    856 
    857   void set_context_switcher(ContextSwitcher* switcher) {
    858     context_switcher_ = switcher;
    859   }
    860 
    861   StringTracker* string_tracker() { return string_tracker_; }
    862 
    863   unibrow::Mapping<unibrow::Ecma262UnCanonicalize>* jsregexp_uncanonicalize() {
    864     return &jsregexp_uncanonicalize_;
    865   }
    866 
    867   unibrow::Mapping<unibrow::CanonicalizationRange>* jsregexp_canonrange() {
    868     return &jsregexp_canonrange_;
    869   }
    870 
    871   StringInputBuffer* objects_string_compare_buffer_a() {
    872     return &objects_string_compare_buffer_a_;
    873   }
    874 
    875   StringInputBuffer* objects_string_compare_buffer_b() {
    876     return &objects_string_compare_buffer_b_;
    877   }
    878 
    879   StaticResource<StringInputBuffer>* objects_string_input_buffer() {
    880     return &objects_string_input_buffer_;
    881   }
    882 
    883   RuntimeState* runtime_state() { return &runtime_state_; }
    884 
    885   void set_fp_stubs_generated(bool value) {
    886     fp_stubs_generated_ = value;
    887   }
    888 
    889   bool fp_stubs_generated() { return fp_stubs_generated_; }
    890 
    891   StaticResource<SafeStringInputBuffer>* compiler_safe_string_input_buffer() {
    892     return &compiler_safe_string_input_buffer_;
    893   }
    894 
    895   Builtins* builtins() { return &builtins_; }
    896 
    897   void NotifyExtensionInstalled() {
    898     has_installed_extensions_ = true;
    899   }
    900 
    901   bool has_installed_extensions() { return has_installed_extensions_; }
    902 
    903   unibrow::Mapping<unibrow::Ecma262Canonicalize>*
    904       regexp_macro_assembler_canonicalize() {
    905     return &regexp_macro_assembler_canonicalize_;
    906   }
    907 
    908   RegExpStack* regexp_stack() { return regexp_stack_; }
    909 
    910   unibrow::Mapping<unibrow::Ecma262Canonicalize>*
    911       interp_canonicalize_mapping() {
    912     return &interp_canonicalize_mapping_;
    913   }
    914 
    915   void* PreallocatedStorageNew(size_t size);
    916   void PreallocatedStorageDelete(void* p);
    917   void PreallocatedStorageInit(size_t size);
    918 
    919 #ifdef ENABLE_DEBUGGER_SUPPORT
    920   Debugger* debugger() {
    921     if (!NoBarrier_Load(&debugger_initialized_)) InitializeDebugger();
    922     return debugger_;
    923   }
    924   Debug* debug() {
    925     if (!NoBarrier_Load(&debugger_initialized_)) InitializeDebugger();
    926     return debug_;
    927   }
    928 #endif
    929 
    930   inline bool IsDebuggerActive();
    931   inline bool DebuggerHasBreakPoints();
    932 
    933 #ifdef DEBUG
    934   HistogramInfo* heap_histograms() { return heap_histograms_; }
    935 
    936   JSObject::SpillInformation* js_spill_information() {
    937     return &js_spill_information_;
    938   }
    939 
    940   int* code_kind_statistics() { return code_kind_statistics_; }
    941 #endif
    942 
    943 #if defined(V8_TARGET_ARCH_ARM) && !defined(__arm__) || \
    944     defined(V8_TARGET_ARCH_MIPS) && !defined(__mips__)
    945   bool simulator_initialized() { return simulator_initialized_; }
    946   void set_simulator_initialized(bool initialized) {
    947     simulator_initialized_ = initialized;
    948   }
    949 
    950   HashMap* simulator_i_cache() { return simulator_i_cache_; }
    951   void set_simulator_i_cache(HashMap* hash_map) {
    952     simulator_i_cache_ = hash_map;
    953   }
    954 
    955   Redirection* simulator_redirection() {
    956     return simulator_redirection_;
    957   }
    958   void set_simulator_redirection(Redirection* redirection) {
    959     simulator_redirection_ = redirection;
    960   }
    961 #endif
    962 
    963   Factory* factory() { return reinterpret_cast<Factory*>(this); }
    964 
    965   // SerializerDeserializer state.
    966   static const int kPartialSnapshotCacheCapacity = 1400;
    967 
    968   static const int kJSRegexpStaticOffsetsVectorSize = 50;
    969 
    970   Address external_callback() {
    971     return thread_local_top_.external_callback_;
    972   }
    973   void set_external_callback(Address callback) {
    974     thread_local_top_.external_callback_ = callback;
    975   }
    976 
    977   StateTag current_vm_state() {
    978     return thread_local_top_.current_vm_state_;
    979   }
    980 
    981   void SetCurrentVMState(StateTag state) {
    982     if (RuntimeProfiler::IsEnabled()) {
    983       // Make sure thread local top is initialized.
    984       ASSERT(thread_local_top_.isolate_ == this);
    985       StateTag current_state = thread_local_top_.current_vm_state_;
    986       if (current_state != JS && state == JS) {
    987         // Non-JS -> JS transition.
    988         RuntimeProfiler::IsolateEnteredJS(this);
    989       } else if (current_state == JS && state != JS) {
    990         // JS -> non-JS transition.
    991         ASSERT(RuntimeProfiler::IsSomeIsolateInJS());
    992         RuntimeProfiler::IsolateExitedJS(this);
    993       } else {
    994         // Other types of state transitions are not interesting to the
    995         // runtime profiler, because they don't affect whether we're
    996         // in JS or not.
    997         ASSERT((current_state == JS) == (state == JS));
    998       }
    999     }
   1000     thread_local_top_.current_vm_state_ = state;
   1001   }
   1002 
   1003   void SetData(void* data) { embedder_data_ = data; }
   1004   void* GetData() { return embedder_data_; }
   1005 
   1006   LookupResult* top_lookup_result() {
   1007     return thread_local_top_.top_lookup_result_;
   1008   }
   1009   void SetTopLookupResult(LookupResult* top) {
   1010     thread_local_top_.top_lookup_result_ = top;
   1011   }
   1012 
   1013   bool context_exit_happened() {
   1014     return context_exit_happened_;
   1015   }
   1016   void set_context_exit_happened(bool context_exit_happened) {
   1017     context_exit_happened_ = context_exit_happened;
   1018   }
   1019 
   1020   double time_millis_since_init() {
   1021     return OS::TimeCurrentMillis() - time_millis_at_init_;
   1022   }
   1023 
   1024   DateCache* date_cache() {
   1025     return date_cache_;
   1026   }
   1027 
   1028   void set_date_cache(DateCache* date_cache) {
   1029     if (date_cache != date_cache_) {
   1030       delete date_cache_;
   1031     }
   1032     date_cache_ = date_cache;
   1033   }
   1034 
   1035  private:
   1036   Isolate();
   1037 
   1038   friend struct GlobalState;
   1039   friend struct InitializeGlobalState;
   1040 
   1041   // The per-process lock should be acquired before the ThreadDataTable is
   1042   // modified.
   1043   class ThreadDataTable {
   1044    public:
   1045     ThreadDataTable();
   1046     ~ThreadDataTable();
   1047 
   1048     PerIsolateThreadData* Lookup(Isolate* isolate, ThreadId thread_id);
   1049     void Insert(PerIsolateThreadData* data);
   1050     void Remove(Isolate* isolate, ThreadId thread_id);
   1051     void Remove(PerIsolateThreadData* data);
   1052     void RemoveAllThreads(Isolate* isolate);
   1053 
   1054    private:
   1055     PerIsolateThreadData* list_;
   1056   };
   1057 
   1058   // These items form a stack synchronously with threads Enter'ing and Exit'ing
   1059   // the Isolate. The top of the stack points to a thread which is currently
   1060   // running the Isolate. When the stack is empty, the Isolate is considered
   1061   // not entered by any thread and can be Disposed.
   1062   // If the same thread enters the Isolate more then once, the entry_count_
   1063   // is incremented rather then a new item pushed to the stack.
   1064   class EntryStackItem {
   1065    public:
   1066     EntryStackItem(PerIsolateThreadData* previous_thread_data,
   1067                    Isolate* previous_isolate,
   1068                    EntryStackItem* previous_item)
   1069         : entry_count(1),
   1070           previous_thread_data(previous_thread_data),
   1071           previous_isolate(previous_isolate),
   1072           previous_item(previous_item) { }
   1073 
   1074     int entry_count;
   1075     PerIsolateThreadData* previous_thread_data;
   1076     Isolate* previous_isolate;
   1077     EntryStackItem* previous_item;
   1078 
   1079    private:
   1080     DISALLOW_COPY_AND_ASSIGN(EntryStackItem);
   1081   };
   1082 
   1083   // This mutex protects highest_thread_id_, thread_data_table_ and
   1084   // default_isolate_.
   1085   static Mutex* process_wide_mutex_;
   1086 
   1087   static Thread::LocalStorageKey per_isolate_thread_data_key_;
   1088   static Thread::LocalStorageKey isolate_key_;
   1089   static Thread::LocalStorageKey thread_id_key_;
   1090   static Isolate* default_isolate_;
   1091   static ThreadDataTable* thread_data_table_;
   1092 
   1093   void Deinit();
   1094 
   1095   static void SetIsolateThreadLocals(Isolate* isolate,
   1096                                      PerIsolateThreadData* data);
   1097 
   1098   enum State {
   1099     UNINITIALIZED,    // Some components may not have been allocated.
   1100     INITIALIZED       // All components are fully initialized.
   1101   };
   1102 
   1103   State state_;
   1104   EntryStackItem* entry_stack_;
   1105 
   1106   // Allocate and insert PerIsolateThreadData into the ThreadDataTable
   1107   // (regardless of whether such data already exists).
   1108   PerIsolateThreadData* AllocatePerIsolateThreadData(ThreadId thread_id);
   1109 
   1110   // Find the PerThread for this particular (isolate, thread) combination.
   1111   // If one does not yet exist, allocate a new one.
   1112   PerIsolateThreadData* FindOrAllocatePerThreadDataForThisThread();
   1113 
   1114   // PreInits and returns a default isolate. Needed when a new thread tries
   1115   // to create a Locker for the first time (the lock itself is in the isolate).
   1116   static Isolate* GetDefaultIsolateForLocking();
   1117 
   1118   // Initializes the current thread to run this Isolate.
   1119   // Not thread-safe. Multiple threads should not Enter/Exit the same isolate
   1120   // at the same time, this should be prevented using external locking.
   1121   void Enter();
   1122 
   1123   // Exits the current thread. The previosuly entered Isolate is restored
   1124   // for the thread.
   1125   // Not thread-safe. Multiple threads should not Enter/Exit the same isolate
   1126   // at the same time, this should be prevented using external locking.
   1127   void Exit();
   1128 
   1129   void PreallocatedMemoryThreadStart();
   1130   void PreallocatedMemoryThreadStop();
   1131   void InitializeThreadLocal();
   1132 
   1133   void PrintStackTrace(FILE* out, ThreadLocalTop* thread);
   1134   void MarkCompactPrologue(bool is_compacting,
   1135                            ThreadLocalTop* archived_thread_data);
   1136   void MarkCompactEpilogue(bool is_compacting,
   1137                            ThreadLocalTop* archived_thread_data);
   1138 
   1139   void FillCache();
   1140 
   1141   void PropagatePendingExceptionToExternalTryCatch();
   1142 
   1143   void InitializeDebugger();
   1144 
   1145   // Traverse prototype chain to find out whether the object is derived from
   1146   // the Error object.
   1147   bool IsErrorObject(Handle<Object> obj);
   1148 
   1149   int stack_trace_nesting_level_;
   1150   StringStream* incomplete_message_;
   1151   // The preallocated memory thread singleton.
   1152   PreallocatedMemoryThread* preallocated_memory_thread_;
   1153   Address isolate_addresses_[kIsolateAddressCount + 1];  // NOLINT
   1154   NoAllocationStringAllocator* preallocated_message_space_;
   1155 
   1156   Bootstrapper* bootstrapper_;
   1157   RuntimeProfiler* runtime_profiler_;
   1158   CompilationCache* compilation_cache_;
   1159   Counters* counters_;
   1160   CodeRange* code_range_;
   1161   Mutex* break_access_;
   1162   Atomic32 debugger_initialized_;
   1163   Mutex* debugger_access_;
   1164   Heap heap_;
   1165   Logger* logger_;
   1166   StackGuard stack_guard_;
   1167   StatsTable* stats_table_;
   1168   StubCache* stub_cache_;
   1169   DeoptimizerData* deoptimizer_data_;
   1170   ThreadLocalTop thread_local_top_;
   1171   bool capture_stack_trace_for_uncaught_exceptions_;
   1172   int stack_trace_for_uncaught_exceptions_frame_limit_;
   1173   StackTrace::StackTraceOptions stack_trace_for_uncaught_exceptions_options_;
   1174   TranscendentalCache* transcendental_cache_;
   1175   MemoryAllocator* memory_allocator_;
   1176   KeyedLookupCache* keyed_lookup_cache_;
   1177   ContextSlotCache* context_slot_cache_;
   1178   DescriptorLookupCache* descriptor_lookup_cache_;
   1179   v8::ImplementationUtilities::HandleScopeData handle_scope_data_;
   1180   HandleScopeImplementer* handle_scope_implementer_;
   1181   UnicodeCache* unicode_cache_;
   1182   Zone zone_;
   1183   PreallocatedStorage in_use_list_;
   1184   PreallocatedStorage free_list_;
   1185   bool preallocated_storage_preallocated_;
   1186   InnerPointerToCodeCache* inner_pointer_to_code_cache_;
   1187   StringInputBuffer* write_input_buffer_;
   1188   GlobalHandles* global_handles_;
   1189   ContextSwitcher* context_switcher_;
   1190   ThreadManager* thread_manager_;
   1191   RuntimeState runtime_state_;
   1192   bool fp_stubs_generated_;
   1193   StaticResource<SafeStringInputBuffer> compiler_safe_string_input_buffer_;
   1194   Builtins builtins_;
   1195   bool has_installed_extensions_;
   1196   StringTracker* string_tracker_;
   1197   unibrow::Mapping<unibrow::Ecma262UnCanonicalize> jsregexp_uncanonicalize_;
   1198   unibrow::Mapping<unibrow::CanonicalizationRange> jsregexp_canonrange_;
   1199   StringInputBuffer objects_string_compare_buffer_a_;
   1200   StringInputBuffer objects_string_compare_buffer_b_;
   1201   StaticResource<StringInputBuffer> objects_string_input_buffer_;
   1202   unibrow::Mapping<unibrow::Ecma262Canonicalize>
   1203       regexp_macro_assembler_canonicalize_;
   1204   RegExpStack* regexp_stack_;
   1205 
   1206   DateCache* date_cache_;
   1207 
   1208   unibrow::Mapping<unibrow::Ecma262Canonicalize> interp_canonicalize_mapping_;
   1209   void* embedder_data_;
   1210 
   1211   // The garbage collector should be a little more aggressive when it knows
   1212   // that a context was recently exited.
   1213   bool context_exit_happened_;
   1214 
   1215   // Time stamp at initialization.
   1216   double time_millis_at_init_;
   1217 
   1218 #if defined(V8_TARGET_ARCH_ARM) && !defined(__arm__) || \
   1219     defined(V8_TARGET_ARCH_MIPS) && !defined(__mips__)
   1220   bool simulator_initialized_;
   1221   HashMap* simulator_i_cache_;
   1222   Redirection* simulator_redirection_;
   1223 #endif
   1224 
   1225 #ifdef DEBUG
   1226   // A static array of histogram info for each type.
   1227   HistogramInfo heap_histograms_[LAST_TYPE + 1];
   1228   JSObject::SpillInformation js_spill_information_;
   1229   int code_kind_statistics_[Code::NUMBER_OF_KINDS];
   1230 #endif
   1231 
   1232 #ifdef ENABLE_DEBUGGER_SUPPORT
   1233   Debugger* debugger_;
   1234   Debug* debug_;
   1235 #endif
   1236 
   1237 #define GLOBAL_BACKING_STORE(type, name, initialvalue)                         \
   1238   type name##_;
   1239   ISOLATE_INIT_LIST(GLOBAL_BACKING_STORE)
   1240 #undef GLOBAL_BACKING_STORE
   1241 
   1242 #define GLOBAL_ARRAY_BACKING_STORE(type, name, length)                         \
   1243   type name##_[length];
   1244   ISOLATE_INIT_ARRAY_LIST(GLOBAL_ARRAY_BACKING_STORE)
   1245 #undef GLOBAL_ARRAY_BACKING_STORE
   1246 
   1247 #ifdef DEBUG
   1248   // This class is huge and has a number of fields controlled by
   1249   // preprocessor defines. Make sure the offsets of these fields agree
   1250   // between compilation units.
   1251 #define ISOLATE_FIELD_OFFSET(type, name, ignored)                              \
   1252   static const intptr_t name##_debug_offset_;
   1253   ISOLATE_INIT_LIST(ISOLATE_FIELD_OFFSET)
   1254   ISOLATE_INIT_ARRAY_LIST(ISOLATE_FIELD_OFFSET)
   1255 #undef ISOLATE_FIELD_OFFSET
   1256 #endif
   1257 
   1258   friend class ExecutionAccess;
   1259   friend class IsolateInitializer;
   1260   friend class ThreadManager;
   1261   friend class Simulator;
   1262   friend class StackGuard;
   1263   friend class ThreadId;
   1264   friend class TestMemoryAllocatorScope;
   1265   friend class v8::Isolate;
   1266   friend class v8::Locker;
   1267   friend class v8::Unlocker;
   1268 
   1269   DISALLOW_COPY_AND_ASSIGN(Isolate);
   1270 };
   1271 
   1272 
   1273 // If the GCC version is 4.1.x or 4.2.x an additional field is added to the
   1274 // class as a work around for a bug in the generated code found with these
   1275 // versions of GCC. See V8 issue 122 for details.
   1276 class SaveContext BASE_EMBEDDED {
   1277  public:
   1278   inline explicit SaveContext(Isolate* isolate);
   1279 
   1280   ~SaveContext() {
   1281     if (context_.is_null()) {
   1282       Isolate* isolate = Isolate::Current();
   1283       isolate->set_context(NULL);
   1284       isolate->set_save_context(prev_);
   1285     } else {
   1286       Isolate* isolate = context_->GetIsolate();
   1287       isolate->set_context(*context_);
   1288       isolate->set_save_context(prev_);
   1289     }
   1290   }
   1291 
   1292   Handle<Context> context() { return context_; }
   1293   SaveContext* prev() { return prev_; }
   1294 
   1295   // Returns true if this save context is below a given JavaScript frame.
   1296   bool IsBelowFrame(JavaScriptFrame* frame) {
   1297     return (c_entry_fp_ == 0) || (c_entry_fp_ > frame->sp());
   1298   }
   1299 
   1300  private:
   1301   Handle<Context> context_;
   1302 #if __GNUC_VERSION__ >= 40100 && __GNUC_VERSION__ < 40300
   1303   Handle<Context> dummy_;
   1304 #endif
   1305   SaveContext* prev_;
   1306   Address c_entry_fp_;
   1307 };
   1308 
   1309 
   1310 class AssertNoContextChange BASE_EMBEDDED {
   1311 #ifdef DEBUG
   1312  public:
   1313   AssertNoContextChange() :
   1314       scope_(Isolate::Current()),
   1315       context_(Isolate::Current()->context(), Isolate::Current()) {
   1316   }
   1317 
   1318   ~AssertNoContextChange() {
   1319     ASSERT(Isolate::Current()->context() == *context_);
   1320   }
   1321 
   1322  private:
   1323   HandleScope scope_;
   1324   Handle<Context> context_;
   1325 #else
   1326  public:
   1327   AssertNoContextChange() { }
   1328 #endif
   1329 };
   1330 
   1331 
   1332 class ExecutionAccess BASE_EMBEDDED {
   1333  public:
   1334   explicit ExecutionAccess(Isolate* isolate) : isolate_(isolate) {
   1335     Lock(isolate);
   1336   }
   1337   ~ExecutionAccess() { Unlock(isolate_); }
   1338 
   1339   static void Lock(Isolate* isolate) { isolate->break_access_->Lock(); }
   1340   static void Unlock(Isolate* isolate) { isolate->break_access_->Unlock(); }
   1341 
   1342   static bool TryLock(Isolate* isolate) {
   1343     return isolate->break_access_->TryLock();
   1344   }
   1345 
   1346  private:
   1347   Isolate* isolate_;
   1348 };
   1349 
   1350 
   1351 // Support for checking for stack-overflows in C++ code.
   1352 class StackLimitCheck BASE_EMBEDDED {
   1353  public:
   1354   explicit StackLimitCheck(Isolate* isolate) : isolate_(isolate) { }
   1355 
   1356   bool HasOverflowed() const {
   1357     StackGuard* stack_guard = isolate_->stack_guard();
   1358     // Stack has overflowed in C++ code only if stack pointer exceeds the C++
   1359     // stack guard and the limits are not set to interrupt values.
   1360     // TODO(214): Stack overflows are ignored if a interrupt is pending. This
   1361     // code should probably always use the initial C++ limit.
   1362     return (reinterpret_cast<uintptr_t>(this) < stack_guard->climit()) &&
   1363            stack_guard->IsStackOverflow();
   1364   }
   1365  private:
   1366   Isolate* isolate_;
   1367 };
   1368 
   1369 
   1370 // Support for temporarily postponing interrupts. When the outermost
   1371 // postpone scope is left the interrupts will be re-enabled and any
   1372 // interrupts that occurred while in the scope will be taken into
   1373 // account.
   1374 class PostponeInterruptsScope BASE_EMBEDDED {
   1375  public:
   1376   explicit PostponeInterruptsScope(Isolate* isolate)
   1377       : stack_guard_(isolate->stack_guard()) {
   1378     stack_guard_->thread_local_.postpone_interrupts_nesting_++;
   1379     stack_guard_->DisableInterrupts();
   1380   }
   1381 
   1382   ~PostponeInterruptsScope() {
   1383     if (--stack_guard_->thread_local_.postpone_interrupts_nesting_ == 0) {
   1384       stack_guard_->EnableInterrupts();
   1385     }
   1386   }
   1387  private:
   1388   StackGuard* stack_guard_;
   1389 };
   1390 
   1391 
   1392 // Temporary macros for accessing current isolate and its subobjects.
   1393 // They provide better readability, especially when used a lot in the code.
   1394 #define HEAP (v8::internal::Isolate::Current()->heap())
   1395 #define FACTORY (v8::internal::Isolate::Current()->factory())
   1396 #define ISOLATE (v8::internal::Isolate::Current())
   1397 #define ZONE (v8::internal::Isolate::Current()->zone())
   1398 #define LOGGER (v8::internal::Isolate::Current()->logger())
   1399 
   1400 
   1401 // Tells whether the global context is marked with out of memory.
   1402 inline bool Context::has_out_of_memory() {
   1403   return global_context()->out_of_memory()->IsTrue();
   1404 }
   1405 
   1406 
   1407 // Mark the global context with out of memory.
   1408 inline void Context::mark_out_of_memory() {
   1409   global_context()->set_out_of_memory(HEAP->true_value());
   1410 }
   1411 
   1412 
   1413 } }  // namespace v8::internal
   1414 
   1415 #endif  // V8_ISOLATE_H_
   1416